Odours or malodours may be generated by many industrial processes and activities as well as occurring through other forms of human activity such as waste disposal into landfill as well as from natural sources.
A number of compositions, methods and processes have been developed in the art to deal with the problem of malodour generation. The source of the malodour is typically one or more of the following chemicals or class of chemicals; evil-smelling and toxic organic sulfur compounds, such as methylmercaptan, dimethyl sulfide and dimethyl disulphide, diallyl sulfide, ammonia, hydrogen sulfide, skatole (3-methyl indole) and the like. With these prior art solutions one strategy has been to treat and/or remove the chemical source of the malodour for example in a waste stream before release into the atmosphere. These strategies require the treatment of process waste streams, both liquid and gaseous before release into the atmosphere. Examples of such malodour control systems are: mist filtration, thermal oxidation/incineration, biofiltration, adsorption, wet scrubbing/absorption, chemical treatment and irradiation.
Despite the availability of various treatment strategies for industrial process waste streams malodour generation from such processes and their related waste continues to be a problem. In addition these solutions directed to industrial waste streams are not applicable to malodour control problems outside of the industrial plant in the open environment, where the malodour is from large area sources of varied and complex composition such as the malodours associated with landfill and other waste disposal sites. In addition these solutions directed to industrial waste streams are not applicable to malodour control problems associated in closed domestic environments where the sources of malodour can again be many and varied and in some instances difficult to determine.
With reference to the problem of malodours in the open environment, one solution is currently provided by Probe Industries and marketed under the trade name AiroNaut™. This solution utilizes spraying techniques where active compositions are deployed as ultra-fine droplets usually along the boundary lines of the area source to suppress malodours. The sprayer is a rotary atomizer, which uses centrifugal action to produce billions of droplets of aqueous composition in the form of a mist or fog.
With reference to the problem of malodours in the domestic environment there are many approaches to solving this problem. A wide variety of deodourizing compositions are known in the art, the most common of which contain perfumes to mask malodour. Odour masking is the intentional concealment of one odour by the addition of another. However preference to perfume is greatly varied and high levels are needed to ensure that the malodour is no longer noticeable. In addition masking does not actually remove the odourous compound or the source of the odour.
Odour modification, in which the odour is changed by, for example, chemical modification, has also been used. Current malodour modification methods known in the art are oxidative degradation, which uses oxidizing agents such as oxygen bleaches, chlorine, chlorinated materials such as sodium hypochlorite, chlorine dioxide and potassium permanganate to reduce malodour, and reductive degradation which uses reducing agents such as sodium bisulfite to reduce malodour.
Other methods of odour control utilize actives that are targeted to react with malodours having specific chemical functional groups. Examples of such actives are; biguanide polymers, which complex with organic compounds containing organically bound N and/or S atoms and fatty alcohol esters of methyl methacrylic acid which react with thiols, amines, and aldehydes. Such actives are limited in the scope of protection which they afford because they only react with limited types of malodour.
Other types of deodourizing compositions known in the art contain antibacterial and antifungal agents which regulate the malodour-producing microorganisms found on the surface to which the deodourizing composition is directed. Many skin deodourant products use this technology. These compositions are not effective on malodours that have already been produced and malodours that do not come from bacterial sources, such as tobacco, food odours or odours from open sources.
There is therefore a continuing need for alternative and/or more effective compositions and methods for open area source malodour control and for malodour control in the domestic environment.